Your first line calculation is already true but reversed. The demand will decrease (that mean the formula would be minus) by 20 gallons for every $0.4 price increase, which means 50 gallons/$. To find the formula you need to insert one sample of either the first equation (65gallon and $3.1) or 2nd equation (45 gallons and $3.5). The formula for demand should be:
q= C - 50p
65 gallon= C- 3.1 * 50
C= 65 gallon + 155 gallon= 220 gallon
The formula would be:
q= 220- 50p
So the second question can be solved by putting 0 on the Q. It would be:
q= 220- 50p
0=220-50p
50p=220
p= $4.4
Multiply using the distributive property
18x + 24
Hope this helps! :)
~Zain
4x=5x-12
subtract 5x from each side
-x=-12
to get a positive x multiply each side by a -1
x=12
Hope I helped :)
The answer is 33417 423x79 =33417
B) 8,000.00 I think that bc he only has 7% on it